In the harvesting of trees, it is typical to mount a tree harvesting apparatus to the boom of a carrier vehicle such as a feller buncher or crawler tractor. The harvesting apparatus referred to herein is typically referred to as a harvesting or cutting head which typically employs a circular cutting saw to sever the tree, a means to grip and hold the tree, comprising a grapple and collector arm, and a base member which partially overlays the circular saw for supporting the tree off of the circular saw as the tree is being cut. Those cutting heads which accumulate the trees on the head itself oftentimes employ a tree accumulation area in which the severed trees are stored and transported. In recent years, machine productivity has become a major issue since the end users of such machines are increasingly under pressure to make a return on their investments in the forestry industry. To this end, it has been found to be desirable to reduce the number of tasks required by the operator while achieving the same productivity levels.
An example of a task that the operator must perform is to manually monitor the tree or trees stored in the accumulation area for any movement or jostling of the trees therein. Should sufficient movement of the trees occur such that the pressure applied by the one or more of the arms to trees is reduced, the operator must manually activate one or both of the arms accordingly to tighten the grip on the tree or trees so as to prevent inadvertent dropping of the trees from the tree harvesting apparatus or premature dumping of the trees by the operator.
The present invention is directed to overcoming one or more of the problems as set forth above.